Authors

1. Juan, Chen Xiao BSN, AdvDipONO
2. Cheng, Lim Lay BSN, AdvDipONO

Abstract

Review question/objective: The objective of this review is to identify the effectiveness of intravenous Lidocaine used to treat pain related to peripheral potassium chloride infusion in adult patients in a hospital setting.

Background: Potassium plays a vital role in the physiological functioning of the human body. Consequently, the level of circulating potassium and other electrolytes in blood is indicative of the wellbeing of the patients. The physiological roles of potassium are as follows: Firstly, it maintains the heart's function by regulating the contraction of skeletal and smooth muscles. Secondly, it causes a direct effect on the cardiovascular system by lowering blood pressure and is suggested to reduce cardiovascular disease mortality.1-2 Thirdly, potassium may prevent and slow down the progression of renal disease by lowering the urinary excretion of calcium.4 Finally, it has been suggested that potassium is associated with metabolic syndrome and may play an important role in glucose intolerance.1-3

Hypokalemia is perhaps one of the most common electrolyte abnormalities in clinical settings. The normal range of serum potassium is 3.5meq/L to 5meq/L. Hypokalemia is defined when the serum potassium level is less than 3.5meq/L and severe hypokalemia is defined when the serum potassium level is less than 2.5meq/L.4 Hypokalemia reflects a disruption in normal homeostasis and occurs among 20% of hospitalized patients.5 The most common cause of hypokalemia is the depletion of potassium ions (K+) due to gastrointestinal or urinary losses caused by vomiting, diarrhea, or diuretic therapy; patients receiving diuretics are at a higher risk of developing hypokalemia.4

The symptoms of hypokalemia generally are not obvious until the serum potassium is below 3.0meq/L.4The consequences of hypokalemia include generalized weakness, lack of energy and muscle cramps. Hypokalemia can be life threatening in patients with ischemic heart disease (IHD), heart failure (HF) and left ventricular hypertrophy (LVH), as low potassium is associated with lethal arrhythmias.6Therefore prompt intervention is crucial to correct hypokalemia and the goal is to prevent and treat life-threatening complications such as arrhythmias, paralysis, rhabdomyosis (muscle weakness) and diaphragmatic weakness.

Intervention to treat hypokalemia usually involves oral replacement and intravenous therapy. Oral replacement is usually preferred in the clinical setting because oral replacement is absorbed by the gastrointestinal tract before it turns into serum potassium. Since oral replacement of potassium does not introduce potassium ions into the blood stream, the induced risk of hyperkalemia is extremely low. Hyperkalemia refers to an abnormally elevated level of potassium in the blood. The normal potassium level in the blood is 3.5 to5.0mEq/L.4,7 Potassium levels between 5.1mEq/L and 6.0mEq/L reflect mild hyperkalemia. Potassium levels of 6.1mEq/L to 7.0mEq/L are indicative of moderate hyperkalemia and levels above 7mEq/L indicate severe hyperkalemia.7

However, in the clinical setting, oral replacement is often restricted by a patient's inability to take medications orally and their gastrointestinal absorption capacity.4 Therefore, intravenous potassium chloride infusion is often used, and has been proven to be a relatively safe method to correct the condition of hypokalemia in about 20% of the hospitalized patients.5,6,7

Intravenous infusion of potassium chloride can cause severe acute pain at the infusion site when the administration of infusion is via a peripherally inserted catheter.9,10,11,12 A peripheral inserted catheter is usually inserted in the veins of the forearm or hand and is less than three inches in length.8 A central inserted catheter usually ends on the right atrium of the heart or Vena Cava.8 The infusion of potassium chloride solution via a central catheter will be directed to the heart first before it transports to the rest of the body systems. In other words, the potassium chloride infusion given via a central line does not need to travel through the veins to reach the heart, and as a result of that, it will not cause any pain along the venous pathway. Therefore, this review will only focus on potassium chloride infused via a peripheral catheter; in other words, we can term it as peripheral potassium chloride infusion as the infusion is administered via a peripheral catheter instead of a central catheter (or called it central line).

The exact etiology of pain associated with peripheral infusion of potassium chloride is not known.12One of the possible etiologies is that potassium chloride is known to be a non-neoplastic irritant agent,13 and being an irritant agent it will tend to cause irritation to the epithelium of the veins as a result of the irritation it causes pain over the infusion site. Another possible etiology is that peripheral potassium chloride infusion has been associated with higher chances on getting phlebitis, thrombosis, infiltration and extravasation in patients who are receiving such infusion, which can again results in pain at the intravenous site and along the vein.14

Pain experienced during peripheral potassium chloride infusion is one of the reasons for patients refusing this treatment method.9,10,11,12Their refusal of treatment could greatly impact on the continuity of supportive treatment and on treatment outcome. In addition, the discomfort experienced by patients during peripheral potassium chloride infusion may give rise to patients' dissatisfaction and/or compliance. According to the Joint Commission International's (JCI) patient care standard, appropriate pain assessment and pain management is a necessity for patients in the acute care setting.15 As an attempt to increase patients' tolerance to peripheral potassium chloride infusion researchers have explored several measures; one of them is the use of Lidocaine either by bolus injection or administering together with the concurrent potassium chloride infusion bag. In particular, in Rapp's study the researchers have added 50mg Lidocaine to KCL 20mmols in 65mls of 0.9% saline, whereas in Morrill's study the researchers have added 10mg of Lidocaine into 10momols of KCL in 50mls of 5% dextrose. In both studies patients' tolerance to pain have improved significantly.10,11 In the third study by Lim, instead of administering intravenous Lidocaine as an infusion the researchers have used a bolus dose of 3mls of 1% Lidocaine prior to intravenous peripheral potassium infusion and it is also reported that patients have less pain and better tolerance to potassium chloride infusion.9

Successful pain management for patients receiving peripheral potassium chloride infusion is an indicator for quality of patient care. Therefore as health care workers, it is our responsibility to ensure the patient's experience is as comfortable as possible when treated in the hospital. It is also our responsibility to find ways and methods to alleviate pain for patients receiving potassium chloride infusion in the hospital setting.

A review of the current literature has suggested intravenous administration of lidocaine in managing the pain at the infusion site while infusing intravenous potassium chloride.9,10,11 Thus far there has not been any systematic review on this topic yet after searching on MEDLINE, EMBASE, Web of Science, CINAHL and the Cochrane Central Register of Controlled Trials. Therefore, the scope of the review will focus on identifying if intravenous Lidocaine is effective in alleviating pain at the infusion site while infusing intravenous potassium chloride via a peripheral inserted catheter.